Bladder fuel pump



June 18, 1963 c. H. TUCKEY BLADDER FUEL PUMP Filed Dec. 27. 1960 ml m2ATTOR/VIYJ' United States Patent 3,094,074 BLADDER FUEL PUMP Charles-H.Tuckey, Cass City, Micl1., assignor to Walbro Corporation, Cass City,Mich., a corporation of Michigan Filed Dec. 27, 1960, Ser. No. 78,428 5Claims. (Cl. 103-44) his invention relates to a bladder fuel pump and isdirected to thecreation of a small, simple fuel pump for small engines.

This application is related to a co-pending application Serial No.766,614, filed October 10, 1958, now matured into Patent No. 2,984,188,issued May 16, 1961.

In the use of small engines for chain saws and other small appliances,frequently it is necessary to tip the engines to various angles even tothe extent of complete inversion. Thus with a gas tank below thecarburetor, an engine will soon stop unless means is provided to supplyfuel to the carburetor. Also in the design of non-invertible engines itstill may be desirable to place the fuel supply below the carburetor fordesign reasons relating to cost and appearance.

With cost a vital factor in the design of these engines in what is now ahighly competitive industry, it has become a problem to provide a simpleand elfective pump to move fuel up into a carburetor from a fuel supply.

The present invention is a result of this problem and has for its objecta simple design, inexpensive, and efiicient.

A further object of the invention is a provision of a pump housinghaving a fastening mechanism directly associated therewith and one whichis adaptable for use with a bladder type diaphragm and also with amodified head for use with a flattypeof. diaphragm.

It is a further object .to provide a pump in which the retaining cap isprovided .with means to circumferentially engage a diaphragm edge to.hold it in extended position.

Another object is the provision of simplified valve mechanism for thepump which provides an effective valve with an extremelylow cost.

Briefly, the invention comprises a pump to be operated from thecrankcase having a bladder type pulsator and so constructed that it maybe made very small and inserted directly in a fuel line or screwed intothe carburetor. The entire pump can be about one inch long andthree-fourths of an inch in diameter.

Other objects and features of the invention relating to details ofconstruction and operation will be apparent in the following descriptionand claims.

Drawings accompany the disclosure and various views thereof may bebriefly described as:

FIGURE 1, a longitudinal section showing the various parts of the pump.

FIGURE 2, a view of the pump body in elevation showing a modified capconstruction.

FIGURE 3, an inside view of a valve recess showing the retainer means.

In FIGURE 1, a construction is shown wherein a cast or molded valvehousing 90 is formed in a cup shape having a bottom 92 and an open lip94 with an annular enlargement 96. In the interior of the cup is anannular recess 98 which can be used for a cylindrical filter screen whendesired.

The cup has at one side a mounting projection 100 which is threaded at102 so that the pump can be threaded directly into the side of an enginehousing which is provided with a tapped hole. On the opposite side ofthe cup is a square projection 104 which can be used for the applicationof a wrench to tighten the pump into position. The bottom of the cup hasa small hollow projection 106 shaped on the outside to hold the end of a3,094,074 Patented June 18, 19,63

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2 tube. In the bottom of .the cup also is a recess 108 ensmalled at 110to serve as an inlet valve chamber for the cup chamber 112.

A small plastic valve disc 114.1ies in the recess portion 110, looselyconfined by a small press fitelement 116 suitably apertured to permitflow past the valve disc when it is sucked back. The element 116 ispreferably square shaped, for example, as shown in. FIGURE 3. In thefastening projection 100 is also a valve chamber 118 having anensmalledportion 120 for holding a valve disc 122 and a retainer 124. The closingcap 121 for the pump comprises a disc 123 and a hose connection nipple125 with a central opening 126. {The diaphragm is composed of asac-likeelement 128 which in the actual size used for production is about 1 indiameter and about in length.

The sac-like element 128 hasa brim 130 whichextends in between the disc123 and the lip 94. The disc 123 has an axially extending annular flange132 with an inwardly extending annular portion 134 which snaps over theenlargement 94 to lock the cap in place, squeezing the annular edge .ofthe brim 130 to hold it in place. Disc 123 has a plurality ofcircumferentially distributed pips 133 which penetrate into theperipheral portion .of brim 130 so that the diaphragm 128 is securelyheld against the lip 94 of the cup-shaped shell 90 by the usual.snap-over arrangement created by flange .132 and annular portion 134.

In FIGURE 2, a similar pump housing is shown with a modified head orcapportion provided with a connecting nipple 1.42. This cap has an enlargedchamber PQrtion 144 which enlarges into an annular portion whichreceives the edges of a flat diaphragm 148. 0n the shoulder between theportions 144 and 150 are provided small pips 146 which penetrate intothe rim of the diaphragm distributed circumferentially around theshoulder so that the diaphragm is securely held against the lip of thecup by the usual snap-over arrangement created by the projecting flange152.

The operation of the embodiment shown in- FIG- URES land 2 is similar.The pulsations of the engine crankcase in a two-cycle engine or possiblyfrom the manifold of a four-cycle engine will cause first an enlargementof the chamber within the diaphragm 128 in FIG- URE 1 and the chamber144 in FIGURE 2, and then an ensmalling of the respective chambers. Thisdraws fuel in through the valve disc 114 on the left-hand side of the'diaphragms while the valve disc 122 was closed against its seat. Thereverse pulsation forces the liquid out of the chamber within thehousing 90 past the valve disc 122 while valve disc 114 is closedagainst its seat. The pump is easily installed in the fuel line of anengine and has the advantage that it can be used as optional equipment,depending on the requirements of the installation.

:The device shown in FIGURE 2 is designed for a slightly larger capacityutilizing higher pressures as, for example, those which occur in themanifold of a fourcycle engine. The fiat diaphragm 148 is held in placeby the small projections 146 which press into the periphery of thediaphragm. The larger chamber portion 144 in the cap allows thisdiaphragm to fluctuate in two directions. As previously stated, theprojection 104 permits a wrench to be applied to the housing to screw itinto place on an internal combustion assembly either into a portion ofthe engine body or that of the carburetor. As shown, the portion 102 ofthe pump can be screwed directly into the carburetor so that fuel can bedischarged directly into the fuel chamber of the carburetor.

Thus, we have disclosed a pump construction which is in overall lengthabout 1 long with a diameter of .3 7 about to 1" which can serve veryeffectively when interposed in a fuel line to move fuel into an internalcombustion engine. It is also possible as will be seen that thediaphragms can readily be replaced if necessary by removal of thesnap-on caps 121 or 140.

I claim:

1. In a small fuel pump adapted to be mounted in and supported by a fuelline of an internal combustion engine for remote operation and whichcomprises, a small elongate hollow shell open at one end, aunidirectional inlet means and outlet means in said shell spaced fromthe open end thereof, a cap for the open end of said shell, said capincluding resilient means, having a snap-over relation thereto, and apumping element in said shell comprising a thin walled, digital-shapedpouch of flaccid material projecting into said shell spaced from thewalls thereof, the margins of said pouch being supported and confinedaround the edges of the open end of said shell between the shell and thecap, said pouch being otherwise unsupported in said shell, said caphaving an opening to receive remote pulsations from the crank case of anengine, that improvement which comprises a radially extending surface onsaid cap to lie directly adjacent a similar radial surface at the end ofsaid shell, wherein the peripheral portions of said pumping element areconfined between said radial surfaces, and circumferentially spacedminute projections around one of said surfaces for projecting intoengagement with the peripheral portions of said pumping element to lockit between said surfaces.

2. A device as defined in claim 1 in which one side of said shell has athreaded projection containing one of said unidirectional means, and adiametrically opposed outof-round polygonal projection on the other sideto serve as a location for the application of torsional pressure to saidshell to fasten said threaded projection to a threaded conduit.

3. A device as defined in claim 1 in which said shell is provided atsaid inlet means with a stepped recess and at said outlet means with asimilar stepped recess; inlet and outlet passages smaller than the boresof said recess leading to the smaller bore of each stepped recess, adisc located in the smaller of each of said recesses, and a confiningmeans in a larger recess adjacent said disc comprising an out-of-roundperforated disc having spaced frictional engagement with the walls ofsaid stepped recess to permit unidirectional flow past said discs fromsaid passages.

4. In a small fuel pump adapted to be mounted in and supported by a fuelline of an internal combustion engine for remote operation and whichcomprises, a small elongate hollow shell open at one end, aunidirectional inlet and outlet in said shell spaced from the open endthereof, a cap for the open end of said shell, said cap includingresilient means, having a snap-over relation thereto, and a pumpingelement in said shell comprising a thin member of flaccid material, themargins of said member being supported and confined around the edges ofthe open end of said shell between the shell and the cap, said memberbeing otherwise unsupported in said shell, said cap having an opening toreceive remote pulsations from the crank case of an engine, thatimprovement which comprises a radially extending surface on said cap tolie directly adjacent a similar radial surface at the end of said shell,wherein the peripheral portions of said pumping element are confinedbetween said radial surfaces, and circumferentially spaced minuteprojections around one of said surfaces for projecting into engagementwith the peripheral portions of said pumping element to lock it betweensaid surfaces.

5. A device as defined in claim 1 wherein said shell has a threadedprojection, said threaded projection having a passageway therethrough,said passageway extending through said shell, one of said unidirectionalmeans being located in said passageway, said shell further having anout-of-round polygonal projection, said out-of-round projection beingadapted to facilitate fastening said threaded projection in tightrelation with a portion of said fuel line.

References Cited in the file of this patent UNITED STATES PATENTS2,556,596 Perkins et al. June 12, 1951 2,690,295 Rand Sept. 28, 19542,830,757 Romanotf Apr. 15, 1958 2,984,188 Tuckey et al. May 16, 1961FOREIGN PATENTS 1,122,901 France May 28, 1956

1. IN A SMALL FUEL PUMP ADAPTED TO BE MOUNTED IN AND SUPPORTED BY FUELLINE OF AN INTERNAL COMBUSTION ENGINE FOR REMOTE OPERATION AND WHICHCOMPRISES, A SMALL ELONGATE HOLLOW SHELL OPEN AT ONE END, AUNIDIRECTIONAL INLET MEANS AND OUTLET MEANS IN SAID SHELL SPACED FROMTHE OPEN END THEREOF, A CAP FOR THE OPEN END OF SAID SHELL, SAID CAPINCLUDING RESILIENT MEANS, HAVING A SNAP-OVER RELATION THERETO, AND APUMPING ELEMENT IN SAID SHELL COMPRISING A THIN WALLED, DIGITAL-SHAPEDPOUCH OF FLACCID MATERIAL PROJECTING INTO SAID SHELL SPACED FROM THEWALLS THEREOF, THE MARGINS OF SAID POUCH BEING SUPPORTED AND CONFINEDAROUND THE EDGES OF THE OPEN END OF SAID SHELL BETWEEN THE SHELL AND THECAP, SAID POUCH BEING OTHERWISE UNSUPPORTED IN SAID SHELL, SAID CAPHAVING AN OPENING TO RECEIVE REMOTE PULSATIONS FROM THE CRANK CASE OF ANENGINE, THAT IMPROVEMENT WHICH COMPRISES A RADIALLY EXTENDING SURFACE ONSAID CAP TO LIE DIRECTLY ADJACENT A SIMILAR RADIAL SURFACE AT THE END OFSAID SHELL, WHEREIN THE PERIPHERAL PORTIONS OF SAID PUMPING ELEMENT ARECONFINED BETWEEN SAID RADIAL SURFACES, AND CIRCUMFERENTIALLY SPACEDMINUTE PROJECTIONS AROUND ONE OF SAID SURFACES FOR PROJECTING INTOENGAGEMENT WITH THE PERIPHERAL PORTIONS OF SAID PUMPING ELEMENT TO LOCKIT BETWEEN SAID SURFACES.